Optical and Dielectric Properties of Transparent Epitaxial GdVO₄/n-GaN/Sapphire Heterostructure

GdVO4 (GVO) thin films were successfully deposited on n-GaN/Al2O3 substrates used as a bottom electrode at 600 degrees C by radio frequency magnetron sputtering. The GVO films annealed at temperatures up to 800 degrees C exhibited epitaxial growth but the films annealed above 900 degrees C showed polycrystalline properties. In the photoluminescence (PL) spectrum, broadband emission was observed at 450 nm for all the films. The auger electron spectroscopy (AES) line-shape of the annealed films was similar to that of the as-deposited film but the Gd/V and Gd/O ratios increased linearly with increasing annealing temperature. The dielectric constant and dielectric loss of the GdVO4 films decreased with increasing annealing temperature with values of 12-26 and 0.04-0.05 at 1 MHz, respectively. (C) 2010 The Japan Society of Applied Physics